Improvement of bioethanol production in cornstalk fermentation through hydrolysis by fungi Trichoderma reesei exposed to gamma rays

Abstract

The utilization of cornstalk as a raw material for bioethanol production is an alternative solution to increase the added value of lignocellulose from agricultural wastes. The glucose content of lignocellulose material can be increased through the hydrolysis process by cellulolytic microorganisms. This research aims to obtain fungi Trichoderma reesei which capable of optimizing glucose content on lignocellulose materials and influence to increase in bioethanol production by Saccharomyces cerevisiae. The experiments were conducted with 2 factorials consist of substrates pre-treatments and hydrolysis. Pre-treatment of substrates by aqua dest (S1), 1% H2SO4 (S2) and 1% NaOH (S3) solution. Treatments of hydrolysis consist of control (K) and fungi T.reesei 750 Gray (H). The fungi T.reesei 750 Gray was obtained from optimizing by gamma rays at a dose of 250, 500, 750 and 1000 Gray. The fungi T. reesei 750 Gy have the specific cellulase activity about 0.24 U/mg higher than the fungi T. reesei 0 Gy about 0.16 U/mg. Pre-treatment of substrates with 1% NaOH (1: 5 w/v) solution and hydrolysis by fungi T.reesei 750 Gray (S3H) is suitable for solid fermentation with S.cerevisiae. After 2 days of solid fermentation by Saccharomyces cerevisiae, the bioethanol contents in S3H medium about 387 ppm while S1K (control) about 196 ppm or increase about 98% (ppm/ppm). This result is expected to be an alternative solution for the utilization of cornstalk for bioethanol production.